Switch having pivoted u-shaped resilient conductive blade

ABSTRACT

The switch has a pair of blades each of which is a piece of flat stock formed into a generally U shape with the shorter leg pivoted on the notched center terminal and normally contacting the N.C. terminal while the longer leg overlies the N.O. terminal. When the actuator (as distinct from the handle) is moved towards the N.O. terminal, the free end engages the terminal with considerable contact pressure while the actuator engages the upstanding tab forcing the blade to the left to wipe the blade on the terminal. The centering spring returns the actuator to normal. When the actuator is moved towards the N.C. terminal, the sloping tab is engaged and the blade wipes the N.C. terminal. In the foregoing the distinction between the actuator and the handle should be kept in mind - the handle moves opposite to the actuator. This switch can handle large DC current without using precious metals, thus achieving greatly improved performance at low cost.

States Patent Comertnrd et al.

[ SWllTCli-ll HAVING PIVOTED Li-SHAPED Primary E.\'aminer-Robert K.Schaefer RESILKENT CONDUCTHVE BLADE Assistant Eraminer-William J. Smith[75] Inventors: John Comertord Chicago; Richard Attorney, Agent, orF1rmM1chael, Best & Friedrich L. Lauritsen, Hoffman Estates, both ofI11. [57] ABSTRACT [73] Assignee: Controls Company of Am i The switchhas a pair of blades each of which is a s m park 1 piece of flat stockformed into a generally U shape with the shorter leg pivoted on thenotched center terl22] Flled: 1974 minal and normally contacting theN.C. terminal while [21] Appl. No; 441,439 the longer leg overlies theNO. terminal. When the actuator (as distinct from the handle) is movedtowards the N.C. terminal, the free end engages the ter- 200/153 G;200/2411 2O0/339 mina] with considerable contact pressure while the ac-[51 llllllt. Cl. lllOlh 23/24 tumor engages the upstanding tab forcingthe blade to [58] Flew Search ZOO/I53 159 the left to wipe the blade onthe terminal. The center- 200/..41, 153 LB, 246, 283, 67 G, 6 B 6 C ispring returns the actuator to normal. When the actuator is movedtowards the N.C. terminal, the slop- [56] References C'ted ing tab isengaged and the blade wipes the N.C. termi- UNlTED STATES PATENTS nal.In the foregoing the distinction between the actu- 2.457.153 12/1948Hubbell 200/153 LB r an he han le should be kept in mind the 3,299,241[/1967 Sayward 200/246 handle moves opposite to the actuator. Thisswitch 3.527.913 9/1970 Gionct 200/6 BB X can handle large DC currentwithout using precious 3.561463 2H97l Long 200/6 C X metals. thusachieving greatly improved performance 3.588.402 6/l97l Heath 200/67 Gat low COSL 3.749.872 7/1973 Foster 200/159 A X 8 Claims, 5 DrawingFigures 1' t/1' ml 1' Hill [11 t 1. l l 36 I t i m I 1 mm =00.

ll W 411'- i/ lml PATENTEBAPRZZIQYS SHKET 1 Eli 2 SWITCH HAVING PIVOTEDU-SI-IAPED RESILIENT CONDUCTIVE BLADE BACKGROUND OF THE INVENTION PriorArt This switch is designed to meet the requirements for the window liftswitch as used in theautomotive industry. The usual switch in thisenvironment employed a leaf spring blade provided with a silver contact,it being usual to employ silver contacts where high switching loads areencountered. Recently, however, the specifications for window liftswitches have been upgraded and the prior switches fail to meet therequirements. Furthermore, the elimination of silver contacts isdesirable to attain lower costs and to reduce consumption of this metal.

SUMMARY OF THE INVENTION The object of this invention is to provide aswitch capable of switching and carrying high DC current at low cost (iewithout use of precious metals). The switch described in the Abstractattains superior performance at low cost. Considerable contact pressureis attained, thus minimizing the detrimental effects of high currentpassing through a point of low contact pressure. Ap proximately 0.020inch (0.5mm) wipe is attained on all three contacts this being adequateto break the contact free should it weld to the terminal as well asinsuring clean contact surfaces.

This switch is designed to meet the needs for automotive window liftrequirements which become severe when the window has been driven to itslimit of motion. resulting in a locked rotor in the motor. In thiscondition the current typically reaches 37 amps DC. This is large enoughto preclude use of many switches over a large number of operatingcycles. The switch is shown paired one blade controlling the *up" modeof the motor and the other controlling the down" mode of the motor. Theuse of this invention is not limited to paired operation a single bladeis useful for many uses and in some instances the N.C. terminal could beomitted.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical section through oneside of the switch with the parts normal.

FIG. 2 is similar to FIG. 1 but the switch is actuated to close the NO.circuit.

FIG. 3 is also similar to FIG. 1 but with the switch actuated in theopposite sense (at which time the other of the pair would close its N.O.circuit) resulting in increased contact force on the NC. terminal andwiping the blade on the N.C. and center terminals.

FIG. 4 is a partial, exploded perspective of the switch elements.

FIG. 5 is an enlarged fragmentary perspective with parts broken away toshow the manner of mounting the switch in the door panel.

DESCRIPTION OF THE PREFERRED EMBODIMENT The present device has two sidesbut is simpler to understand if the initial description is confined toone side of the switch which is an operative switch by itself. In FIG. 1one half or side of the complete switch is illustrated.

The switch has a'housing 10 in which three spaced terminals are mounted.These terminals are designated both 12,14,16 and NO M and NCrespectively. The housing is divided by a partition or barrier 18separating the switching on one side of the housing from the switchingon the other side. This is an electrical barrier. Switch blade 20 isbent into a generally U shape with a short leg 22 and a long leg 24. Thefree end 26 of the short leg 22 is bent downwardly and rests on terminal14 to function as the pivot of the blade. The short leg is slightly bentat 28 to form a surface adapted to engage terminal 16. The free end 30of the long leg is bent down to overlie terminal 12. The actuator 32 haspoint 34 bearing against the long leg 24 of the blade 20 and has arounded shoulder portion 36 which is received in a cylindrical cavity 38in the housing cover 40 so as to, in effect. make the actuator pivotabout the center of the curvature of the shoulder 36 (or cavity 38).This center lies on the centerline of the switch housing. The actuatorpoint 34 bears against the resilient blade off center (to the right).Leaf spring 42 passes over the flat 44 on the upper portion of theactuator with the ends of the leaf spring bearing against the undersideof the cover 40 at 45,46. The leaf spring, therefore, exerts a forcereturning the actuator to the normal position illustrated in FIG. 1.

The cover is secured to the housing 10 by suitable means such as sonicwelding. The cover is provided with a slot 48 through which the actuatortab 50 projects. Handle 52 is pressed onto the tab 50.

In the position illustrated in FIG. 1 with the actuator point 34engaging the blade to the right of pivot 26 (which is the normalposition), the blade will contact the NC, (16) terminal. If the actuatoris now moved to the left (bear in mind that when the actuator 32 movesto the left the handle 52 moves to the right) the vertical face 54 ofthe actuator will strike the tab 56 standing up vertically from the longleg 24. Prior to striking the tab, however. the actuator point 34 willbe moving about its center of rotation and, therefore, closer to thepivot 26, thus forcing the end 30 of the blade downwardly into contactwith terminal 12 (NO,) as shown in full lines in FIG. 2. After the freeend of the blade contacts the terminal, the flat face 54 of the actuatorwill engage the tab and push against the tab as movement of the actuatoris continued. This causes the blade to wipe across the terminal 12 asillustrated in dotted lines in FIG. 2. This wiping action keeps thecontacts clean and breaks any welds that may be formed when switchinghigh DC loads. When the handle 52 is released, the actuator is returnedto the neutral position of FIG. 1.

If the actuator is moved to the right as in FIG. 3, the actuatorv point34 will ride up the incline tab 58. Since the blade was already incontact with terminal NC no switching action is accomplished by thisbut, depending on the slope of the ramp, a lateral force may betransmitted to the blade causing the blade to slide on both terminals 14and 16 with the beneficial results noted above. If the slope (curve) oframp 58 matches the arc of actuator point 34 (as shown in FIG. 3 in fulllines) there will be no wiping action. If the slope is greater, thepoint pushes the ramp and causes the blade to be moved to the right,causing the wiping action on terminals 14,16 (dotted in FIG. 3). If theslope is less (or the tab 58 eliminated) there is no wipe and the freeend 30 of the blade will rise as the actuator moves to the right.

It will be appreciated that in H6. I there is an electrical path fromterminal 14 through the blade to terminal 16. This is the normalcondition. The same path is completed in H6. 3 while in FIG. 2 theelectrical path is from terminal 14 to terminal 12 and the electricalconnection to terminal 16 has been broken. In the specific use for whichthis switch was designed, the center terminal M is connected to a DCmotor while terminal 16 is connected to ground. Thus in the normalposition the motor is grounded. When the switch is actuated as in FIG.2, however, the motor lead M is now connected to terminal 12 which isconnected to the positive side of the automotive electrical system toenergize the motor.

As noted above. this switch is designed to be used as a pair asillustrated generally in FIG. 4. It will be seen that the blades areoppositely disposed when viewed from one side but if one were to look atone side and then turn the switch around and look at the other, the

blades would appear the same. When the actuator 32 is moved in a givendirection, it will, for example, close the circuit from NO, to M on theright side of FIG. 4 while maintaining the circuit from NC to M on theleft side of FIG. 4. Motor mode No. l is actuated. Then when the switchis actuated in the opposite direction, motor mode No. 2 will beenergized since terminal M is then connected to the positive terminaldesignated NO while the right side of FIG. 4 would merely main tain thegrounding of motor mode No. 1.

Just one side of the switch can be used as a simple switch completing acircuit from 12 to 14 in which case terminal 16 would not be necessary.Or it could be used to break a circuit from 14 to 16. Or the unit shownin FIG. 1 can be used without the other side" of the complete product.

We claim:

1. A switch comprising,

a housing,

spaced terminals mounted in the housing,

an electrically conductive resilient blade formed in a generally U shapehaving a long and a short leg with the end of the short leg pivoted onone terminal and the long leg normally overlying and spaced from theother (N.C.) terminal with the U bend in the blade being spaced from thesaid one terminal in the direction opposite that of said other terminalrelative to said one terminal,

an actuator pivotally mounted in the housing and normally engaging thelong leg of the blade at a point lying between said bend and animaginary line from said pivot to the pivot center of the actuator,

movement of said actuator to move the point of contact of the actuatorwith the blade past said imaginary line to an active position beingoperative to force the free end of the long leg of the blade intocontact with said N.O. terminal.

2. A switch according to claim 1 in which the long leg of the blade isprovided with an upstanding tab which is engaged by the actuator whenthe actuator moves from its normal position to said active positionwhereby continued motion of the actuator after the blade end contactssaid N.O. terminal is operative to force the end of the long leg to wipeacross said other terminal.

3. A switch according to claim 1 including a third (N.C.) terminalmounted in the housing in proximity to the bend of the blade andnormally engaged by the short leg of the blade when the actuator is inits normal position, said short leg being moved out of contact with saidN.C. terminal when the actuator is moved to its active position andcontact pressure between the blade and the N.C. terminal increasing whenthe actuator is moved from said normal position in the directionopposite the active position.

4. A switch according to claim 3 in which the long leg of the blade isprovided with an upstanding tab which is engaged by the actuator whenthe actuator moves from its normal position to said active positionwhereby continued motion of the actuator after the blade end co'ntactssaid N.C. terminal is operative to force the end of the long leg to wipeacross said other terminal.

5. A switch according to claim 4 in which the blade is provided with asecond tab sloping upwardly from the long leg on the side of theactuator opposite the first or upstanding tab, the second tab beingengaged by the actuator when the actuator is moved in said oppositedirection whereby the contact pressure between the short leg and saidN.C. terminal and the wiping motion of the blade across the N.C.terminal are increased as a function of the angle between the second taband the blade.

6. A switch including a second blade and terminal arrangement as definedin claim 5 arranged alongside the arrangement of claim 5 but in theopposite sense whereby a single actuator acting on both blades isoperative to close the NO. terminal in one switch when moved in onedirection and to close the other N.O. terminal when moved in theopposite direction.

7. A switch including a second blade and terminal arrangement as definedin claim 1 arranged alongside the arrangement of claim 1 but in theopposite sense whereby a single actuator acting on both blades isoperative to close the NO. terminal in one switch when moved in onedirection and to close the other N.C. terminal when moved in theopposite direction.

8. A switch comprising,

a housing,

spaced terminals in the housing,

an electrically conductive resilient blade bent into a generally U shapewith the free end of one leg pivoted on one terminal,

an actuator pivotally mounted in the housing and normally engaging theother leg at a point offset from the imaginary line connecting thecenter of the actuator pivot and the pivot of said blade, movement ofsaid actuator to move the point of engagement with the blade throughsaid imaginary line being operative to move the blade relative to saidother terminal.

1. A switch comprising, a housing, spaced terminals mounted in thehousing, an electrically conductive resilient blade formed in agenerally U shape having a long and a short leg with the end of theshort leg pivoted on one terminal and the long leg normally overlyingand spaced from the other (N.O.) terminal with the U bend in the bladebeing spaced from the said one terminal in the direction opposite thatof said other terminal relative to said one terminal, an actuatorpivotally mounted in the housing and normally engaging the long leg ofthe blade at a point lying between said bend and an imaginary line fromsaid pivot to the pivot center of the actuator, movement of saidactuator to move the point of contact of the actuator with the bladepast said imaginary line to an active position being operative to forcethe free end of the long leg of the blade into contact with said N.O.terminal.
 2. A switch according to claim 1 in which the long leg of theblade is provided with an upstanding tab which is engaged by theactuator when the actuator moves from its normal position to said activeposition whereby continued motion of the actuator after the blade endcontacts said N.O. terminal is operative to force the end of the longleg to wipe across said other terminal.
 3. A switch according to claim 1including a third (N.C.) terminal mounted in the housing in proximity tothe bend of the blade and normally engaged by the short leg of the bladewhen the actuator is in its normal position, said short leg being movedout of contact with said N.C. terminal when the actuator is moved to itsactive position and contact pressure between the blade and the N.C.terminal increasing when the actuator is moved from said normal posItionin the direction opposite the active position.
 4. A switch according toclaim 3 in which the long leg of the blade is provided with anupstanding tab which is engaged by the actuator when the actuator movesfrom its normal position to said active position whereby continuedmotion of the actuator after the blade end contacts said N.O. terminalis operative to force the end of the long leg to wipe across said otherterminal.
 5. A switch according to claim 4 in which the blade isprovided with a second tab sloping upwardly from the long leg on theside of the actuator opposite the first or upstanding tab, the secondtab being engaged by the actuator when the actuator is moved in saidopposite direction whereby the contact pressure between the short legand said N.C. terminal and the wiping motion of the blade across theN.C. terminal are increased as a function of the angle between thesecond tab and the blade.
 6. A switch including a second blade andterminal arrangement as defined in claim 5 arranged alongside thearrangement of claim 5 but in the opposite sense whereby a singleactuator acting on both blades is operative to close the N.O. terminalin one switch when moved in one direction and to close the other N.O.terminal when moved in the opposite direction.
 7. A switch including asecond blade and terminal arrangement as defined in claim 1 arrangedalongside the arrangement of claim 1 but in the opposite sense whereby asingle actuator acting on both blades is operative to close the N.O.terminal in one switch when moved in one direction and to close theother N.O. terminal when moved in the opposite direction.
 8. A switchcomprising, a housing, spaced terminals in the housing, an electricallyconductive resilient blade bent into a generally U shape with the freeend of one leg pivoted on one terminal, an actuator pivotally mounted inthe housing and normally engaging the other leg at a point offset fromthe imaginary line connecting the center of the actuator pivot and thepivot of said blade, movement of said actuator to move the point ofengagement with the blade through said imaginary line being operative tomove the blade relative to said other terminal.